Nitrogen management

Press, 9 October 1987, Page 31

Nitrogen management

Optimum nitrogen management in wheat is essential if maximum yield and quality are to be obtained, believes Mr Kim Stevenson, an agronomy consultant with the M.A.F. at Lincoln. In milling wheats, a positive relationship between grain protein content and average bake score has been observed. Thus the timing of nitrogen application in crops grown for bread production is important. Earlier, more traditional nitrogen applications are associated with maximum yield formation while later applications (after first node stage) give much greater responses in grain protein content. Although impossible to detail a management system in a newspaper to suit

every individual farmer, Mr Stevenson suggested milling wheat growers consider the following points when deciding on optimum nitrogen management:— • What is the realistic yield potential of the paddock? • What is the paddock fertility? • What is the optimum way to split the nitrogen between the different application times of drilling, early tillering, late tillering and "in boot” stages? Nitrogen should be applied at drilling only in extreme circumstances. Nitrogen at early tillering or earlier has been traditional for maximum yield formation, and low nitrogen status at this stage often leads to reduced yields. If/paddock fertility is low ' or high

leaching has occurred, some nitrogen may be required to keep the crop growing. Sap nitrate strips are a useful indicator of a plant’s nitrogen status. Main nitrogen application may occur around late tillering, giving a response in both yield and grain protein content. The farmer should assess how the crop is growing, thelikelihood of disease and water stress occurring and previous nitrogen inputs in deciding on how much nitrogen to apply at this stage. Nitrogen applications at late stem elongation to ear emergence should be considered where the crop is developing very well and there is going to be a large demand for nitrogen; water supply is not going to be limiting; it is convenient to drive over the crop at this late stage; and there is a premium paid for quality, particularly high protein content.